1. Technical Field
The present invention relates to a skyrmion driving method and driving apparatus that utilize electric current to make it possible to perform driving ON-OFF control at high speed and to suppress the influence of an inertial effect so that the driving control can be performed further logically.
2. Related Art
In conventional semiconductor electronics, among two properties of electrons which are electric charges and spins, focus has been mostly given to utilization of electric charges. On the other hand, spintronics that actively utilizes the other property of electrons, spins, is also an electron technique that has been of particular interest these years, and is highly expected to provide next-generation devices having innovative features/functions.
Spins of electrons generally are largely related to magnetic behaviors of a material, and when spins align in the same direction, the material shows normal properties as a magnetic body. In contrast, it has been made clear that in some special magnetic bodies, spins of electrons voluntarily form a structure called a skyrmion.
A skyrmion is a topological magnetic structure in which the order of spins generated in a material shows a spiral array. A skyrmion has a very stable structure without any breakage even when continuous changes have occurred to spins.
In this manner, a structure in which a skyrmion is regularly arrayed in a grid under a magnetic field at a certain temperature is called a skyrmion crystal, which was found through analysis of B20-type MnSi by utilizing a small angle neutron beam diffraction method. A skyrmion crystal can be observed directly through observation of a B20-type alloy by utilizing a Lorentz transmission electron microscopy (TEM).
Because the size of a skyrmion is approximately 3 to 100 nm in diameter, a skyrmion is expected to provide next-generation spintronics device having a high information density.
Also, a skyrmion shows characteristics which are excellent from the engineering perspective because it allows control of a magnetic structural body with micro-electric current whose magnitude is as small as approximately 1/100000 as compared with a magnetic domain wall in a ferromagnetic body.
Also, a skyrmion generated in a crystal has a property of functioning as an effective magnetic flux through the quantum-mechanical Berry phase for electrons. Because of this, it can be known that the topological Hall effect occurs to a skyrmion crystal.
Furthermore, a skyrmion crystal also shows other interesting properties. For example, exemplary properties include that a skyrmion shows a behavior little influenced by the pinning effect at a very low power density (<100 Acm−2), and that electric polarization occurs due to a skyrmion in an insulator.
Because a skyrmion has numerous peculiar properties like these, it is expected to be applied to highly dense, power-saving data devices and applied to arithmetic operation devices. Also, because by having a special spin array, a skyrmion has a property as particles, and is configured in nanometer sizes, it is expected to be applied for recording bits in high speed, power-saving magnetic memory elements.
When utilizing a skyrmion having such properties as an information carrier, it is required to control driving of it.